The lecture has been given on Dec. 18th, 2010 by Dr. Mohammad Shaikhani.

1. Dr.Mohammad Shaikhani DISORDERS OF THE NEUROMUSCULAR JUNCTION MYASTHENIA GRAVIS

9. Investigations

15. Differences between MG & Myasthenic (Eaton-Lamberts) syndrome: MS MG 1.Autoimmune immunological attack on presynaptic membrane limiting the release of ACH. 2.Mosrly paraneoplastic : in 2/3 of cases due to oat cell Ca. of the lungs > 40 ys . of age & 1/3 non neoplastic occuring at any age. 3.Realative sparing of extra ocular & bulbar muscles . 4.Autonomic dysfunction occur in 50% of cases. 5. EMG shows decreases amplitude of contraction with single nerve stimulation , but repetitive stimulation at frequencies > 10htz produces normal amplitude. 6. Treatment: ACH estrase inhibitors has minimal effect. Paraneoplastic type needs management of underlying cancer with guanidine & diaminopyridine having some benefits. For nonneoplastic type steroids + atzathioprine can control immuologocal attack. 1. Postsynaptic ACH receptors Abs. 2.All autoimmune type 3. 3.Common . 4.Not present, 5.Just contrary to that. 6.Good response to ACH estrase inhibitors.

19. Disease of muscles: MUSCULAR DYSTROPHIES Type Genetics onset Muscles affected Other features Myotonic dystrophy (DM1) AD; triplet repeat chr19q Any Face (ptosis), sternomastoids, distal limb, generalised later Myotonia, cognitive dulling, cardiac conduction abnormalities, lens opacities, frontal balding, hypogonadism Proximal myotonic myopathy (PROMM; DM2) AD; chr 3q Adult Proximal, esp thigh, sometimes muscle hypertrophy As for DM1 but cognition not affected, Muscle pain Duchenne XL; deletd dystrophin gene 1st 5ys Proximal/ limb girdle Pseudohypertrophy of calves Cardiomyopathy, Gower sign +ve:patient climbs thigh by hand to stand Becker XL; deled dystrophin gene LC/EA Proximal/limb girdle Pseudohypertrophy of calves Cardiomyopathy Gower +ve.

20. Disease of muscles: MUSCULAR DYSTROPHIES Limb girdle AD (type 1) AR (type 2) different chromosomes Childhood/early adult Limb girdle Some have calf hypertrophy Some have cardiac conduction abnormalities Facioscapulohumeral (FSH) AD; chromosome 4q 7-30 ys Face/ upper limb girdle Pain in shoulder girdle common Oculopharyngeal AD/AR recessive; chromosome 14q 30-50 years Ptosis, external ophthalmoplegia, dysphagia, tongue weakness Mild lower limb weakness Emery-Dreifuss XLR; mutations in emerin gene 4-5 years Humero-peroneal, proximal limb girdle later Contractures early Cardiac involvement leads to sudden death

22. 1.Myasthenia gravis can be associated with: A. Presynaptic antibodies. B. Thymoma. C. Thymic hyperplasia. D. Skeletal muscle antibodies. E. Other autoimmune diseases.

23. 2.M2yasthenia gravis &Thymic hyperplasia: A. Most cases have the disorder. B. Chest X Ray is indicated in every cases. C. Thymic surgery is indicated in every case. D. Thymic hyperplasia makes prognosis worse. E. Thymic hyperplasia occur in elderly patients.

24. 3.Thymoma with myasthenia gravis: A. Makes prognosis worse. B. Occurs in elderly. C. Associated with skeletal muscle antibodies. D. More common than Thymic hyperplasia. E. Makes the disease more severe.

25. 4.Diagnosis of myasthenia gravis can be supported by: A. Positive tensilon test. B. Ice on Eyes test. C. Number counting test. D. Ach antibodies. E. Anti skeletal muscle antibodies.

26. 5. The following suggest cholinergic crisis rather than myasthenic crisis: A. Sweating. B. Salivation. C. Severe Paralysis. D. Pallor. E. Respiratory failure.

27. Myasthenia Gravis